What is a Secchi Disc? A Secchi disc is an 8-inch diameter metal disc painted in alternative black and white quadrants used to measure water clarity. Water clarity is a quick way to estimate lake health, and it plays an important role in determining the types of plants and animals that a waterbody can support.

General Guidelines:

"Ice On"

In case the lake should be frozen in the morning, after a cold calm night, ut then breaks up in the afternoon with wind and sun, I don't count that as a freeze-up date. However, if a lake freezes on one day, stays frozen for a few days, then breaks up for some days before a final freeze-up for the winter, I record all the freezing and opening dates so that I can determine the total number of days each winter that the lake was covered with ice - regardless of whether it is safe for walking. In the simplest case, a lake may freeze on one day and then stay frozen all winter. In some winters, however, the freeze-up process can be quite complex with multiple freezing and openings.

"Ice Off"

The lake is considered thawed when it is possible to boat from any shore to the deepest part of the lake without encountering ice.